Oil and water emulsions are commonly formed, and/or present, in the oil-field production industry, the petroleum refining industry, the petrochemical industry, activities related to such industries, such as the transportation of oil and oil products, and other industries which can produce oil and water emulsions, such as the food preparation industry.
For instance, in oil field production, additional oil can be recovered from a formation by waterflooding. This technique of oil recovery involves the injection of water into the oil production formation in secondary or tertiary water floods thereby displacing the oil. The success of a water flood operation is dependent on the effectiveness by which the water replaces oil from the pores of the rock or sand formation. One technique used to achieve this displacement is to reduce the interfacial tension between the oil and water phases. The addition of surfactants to the injection fluids reduces the interfacial tension between the oil and water phases. The net result is an improved displacement of oil from the pores of the formation.
However, the use of surfactants to reduce the interfacial tension causes a stable oil and water emulsion to be formed.
Emulsions in the petroleum refining industry can include emulsions prepared under controlled conditions from crude oil and relatively soft waters or weak brines (crude desalting). Controlled emulsification and subsequent demulsification are of significant value in removing impurities, particularly inorganic salts from crude oil.
Other emulsions can be formed in the waste oil recovery systems in the petroleum refining and petrochemical industries.
Emulsions can also be formed as a result of oil spills on water, at the interface between the oil spilled and the water.
These emulsions can be difficult and expensive to demulsify by application of the usual demulsifiers and treating techniques. In addition, the demulsifying of emulsions is not only useful for the recovery of the oil but is also, in many cases, necessary in order to discharge the wastewater from such processes. In fact, the cost to treat such waste waters to acceptable levels of oil for discharge can be quite high and can include the use of processing equipment, such as clarifiers.
Therefore, it is desirable to develop compositions and processes which demulsify emulsions economically and rapidly and that provide water with low oil content.